5751's

[defride]

I've an Aesthetix Calypso and noise has been the only thing that has disappointed me about it slightly. All the tube combinations I've used in my system have produced audible white noise up to 4-5ft away. Occaisionally noticeable from the listening chair at night during a quiet passage but otherwise not intrusive. In friends systems the noise hasn't been noticeable at all.

While it's always been in the back of my mind that the noise must be masking microdynamics I've been very happy with it from a sound quality point of view.

I settled on 5751's to reduce the gain, get some more range on the vol control and I got the impression that they are generally of high quality. I tried a few and settled on a matched pair of Sylvania Gold Brand, they offer up a really delicous rich and textured sound without any loss of transparency. On the other side of the amp Mullards made a big difference and I settled on a pair of CV2493s after trying a few.

So, I picked up a pair Sylvania 5751s (50hrs...?) off another forum from a long term member that I didn't know as they were cheap and I figured they'd make a great back up. Well well, surprise surprise, finally popped them in and no noise, ear up to the tweeter and a faint rustle. Wow, didn't think it was possible in my system. Well it is, and after a couple of hours settling the system is sounding very good indeed. The Gold Brand are destined for storage in case of emergency!

Any experience of other 5751's out there?

 

[LL21]

You could also call Brent Jessee, Upscale Audio or Andy's Vintage Tube Service...I've had great help, advice and bought tubes from each of them.

 

[mep]

The problem with all tubes is that once you hit the power switch and un-mute the preamp on any given day, you never know what you are going to be faced with. Tubes can be silent one day and go to hell the next. It's part of the fun when dealing with tubes. If you try and use a pure-tube phono preamp to amplify low-output MC cartridges, the risk of going gray and/or pulling out your hair is greatly increased. Enjoy your low noise performance you have right now. Savor it every day.

 

[Phelonious Ponk]

Congrats on your recovery. White noise you could hear through quiet passages from five, six feet away had to be killing your dynamics. I'm not sure you could even call that high fidelity.

Tim

 

[microstrip]

If you owned a top car would you buy replacement parts and consumables at flea markets without any professional help? Most tube equipment owners have problems because of the quality of the tubes they put in their equipment. Buying from trusty sources and debating the choices with the manufacturer of the equipment or your competent dealer will save a lot of problems. I have a few friends with tube equipment. The big trouble starts the day they decide to start buying tubes on their own from the net ...

 

[defride]

Some interesting comments so far, keep them coming, its all constructive, I'm only 18 mths into my experience with tube equipment.

The expensive tubes I bought came from recommended sources, these new ones were just a punt as they were less than $50 for a matched pair which I knew I could sell on and only planned to keep as spares/try. As it's turned out it seems the punt has paid off in a way I'd never envisaged and opened my eyes.

Brent Jesse has a great site with great information, I've visited as a reference whenever I've been interested in a set of tubes. Unfortunately buying from the US is a bit of a problem from here in Europe as we're hit with significant taxes, a $300 pair of tubes to you over there would cost $400+ to land here...

The Calypso is a great sounding piece. I've preffered it in my system to a few other more expensive pre's. As it comes with a reputation for noise I assumed it was inherent. Used with Yamaha NS1000, Neat MF7 and Revel Gem recently noise was not at all noticeable so I assumed the system dependent reputation was correct. That the noise can be mitigated almost entirely by careful tube selection is a big surprise and another experience to rack up on the journey. It's only since reading this site that I've learnt tubes can be graded for noise and microphonics.

 

[gamve]

I've always thought a reasonable 5751 is a much better tube than a very good 12AX7. Just my opinion.

 

[microstrip]

Unfortunately the George Kaye Small Signal Tube Checker is no more available - it was the best checker for amateur use. It is basically a very simple preamplifier circuit with an audio amplifier and an headphone socket and is great to check individual tubes for microphony and noise. If you are a DIY person you can easily built one yourself - or just buy one cheap chinese one tube preamplifier kit from eBay using the tube you want to test - the 5751 is pin compatible with the 12AX7 family.

 

[es347]

..and that's why the good Lord gave us n-p-n junctions..

 

[microstrip]

..and that's why the good Lord gave us n-p-n junctions..

That have many types of noise that do not show in classical measurements and are only known and understood by a few experts in audio design that are not interested in teaching us ...